problem with layout in ICU 2.6

Hello,

I am working on backporting the Khmer layout engine to ICU 2.6 because Open 
Office 2.0 will use this version of ICU in its code and I would like to have 
Khmer supported there.

I get a problem during my test which I can not solve and that is not present 
in the latest ICU. 
Every time a CR character is in a run of Khmer characters this character is 
filtered in the charMapper so that the result is one character shorter then 
the input. But later on the code creates mappings between characters and 
glyphs and here the filtered character is skipped and a not entry is created 
in the map for the CR. This leads to a problem in ParagraphLayout::appendRun, 
because here the code tries to find the left and right glyph what fails 
because of the missing entry in the map. 

Is this a known bug or did I made a mistake in backporting the Khmer layout 
engine? 

Sorry for bothering you with a question about an old version.

Jens